Aircraft gas turbine arrangement



Nov. 33, 3945. E. a CLARK AIRCRAFT GAS TURBINE ARRANGEMENT 2Sheets-Sheet '1 Filed July 9, 1940 Inventor":

I Eggene' S; Clark,

7v HI Nov. 13, i945.

AIRCRAFT GAS TURBINE AR RANGEMENT Filed July 9, 1940 2 Sheets-Sheet 2Inventor": El gene S. Clark,

His Attorney.

E. s. CLARK I 2,388,952

Patented Nov. 13, 1945 j UNITED STATES- L PATENT OFFICE,

Eugene S: Clark, flynn, Masa, assignor'to Gen eral Electric Company, acorporation vof New York Application July 9, 1940, Serial No. 344,562

4 Claims.

turbine arrangements such as are used for driv- .ing accessories, likeblowersor compressors to supercharge internal combustion engines andcabins. More specifically the invention relates to flight hoods forconducting gase's discharged from the gas turbine to the atmosphere.

Whenever aircraft gas turbines areoperated with gases exhausted from thecombustion engine, it is customary to provide the conduit for conductinggases from the exhaust manifold of the engine to the turbine with avalved wastegas conduit for discharging part of the gases and secured tothe compressor casing It by directly into the atmosphere andtforcontrolling such discharge in order to regulate the power ,output of thegas turbine. Difficulties have -heretofore been experienced inconducting the waste gases to the atmosphere without causing injury toor without affecting apparatus in proximity to the waste gate.

out mixing with the turbine exhaust gases in proximity to the turbine.

For a better understanding of what I believe p The object of myinvention is' 'an improved The present invention relates to aircraft gasand the compressor, surrounding in spaced rela-.

tion the bearing l4, and having a row of nozzle blades ll for directinggases to the wheel. In order to reduce the radiation of heat from thenozzle box to the bearing an annular' curved baflie i 8 is providedadjacent to the nozzle box surrounding the bearing I4 in spaced relationa plurality of bolts l9. I

A device'20 for cooling and protecting the bucket wheel from the gasesdischarged there from is' arranged adjacent the outlet side of thebucket wheel. The cooling and protecting device 20 comprises a cap 2|concave-shaped to wards the wheel and having a rim portion in closeproximity-to the wheel. This cap prevents gases discharged from thewheel, more particu-- larly from the leading portion thereof, from beingforced towards the central portion of the wheel and causing excessiveheating thereof. By

v a leading portion of the wheel I mean a portion facing the slipstream,it being assumed in this to be novel and my invention, attention is'directed to the following description and the claims appended theretoin connection with the accompanying drawings.

In the drawings Fig. 1 is a view partly in sec-.'

tion of an aircraft gas turbine arrangement embodying my invention; Fig.2 is a front view of Fig. 1; Fig. 3 is a section along line 33 of Fig.

2; and Fig. 4 is an enlarged detail view of a part I 4 of Figs. 1 and 2.

the turbine are conducted from any suitable source such as the exhaustmanifold of the combustion engine (not shown) by means of a, flangedconduit l5 to a nozzle box is of the turbine. The latter is locatedbetween the turbine wheel instance that the direction of the slipstreamis in the direction of a diameter of .the wheel, and that thearrangement is operated without a flighthood. The slipstream directionis marked by an arrow in, Fig. l of the drawings.

a diameter of the latter and has an inlet portion connected to a conduit.23 for receiving cooling medium, such as air, from the slipstream. Thelower end portion of the conduit 22 and the cap 2| form a dischargeopening 24 through which cooling'air is discharged towards a trailingportion of the rim of the bucket wheel. An extension 25 of the coolingconduit 22 is detachably secured to and supported on the nozzle box IEby means including brackets 26. The inletportion of the conduit 22 isdetachably supported on the nozzle box IE by brackets 21. Thearrangement so far described is more fully disclosed in theaforementioned application of C. W. L

A part of the gases in the supply conduit [5 are discharged directlyinto the atmosphere, that is, bypassed with regard to the turbinethrough a waste gas conduit 28 including a waste from to theatmosphere." According to my invention, as pointed out above, I providea com- Astreamlined conduit 22 is secured to the cap 2| across weldedtogether and forming a discharge openforming a discharge opening in thedirection of the-slipstream so that the ,slipstream oi the airplane mamynot interfere with the discharge of by the central or main channeldefined between the outer and inner walls 32, 33 of the flighthood andthe partitions 53,54. Waste gases discharged during operation throughthe waste gate conduit 28 areconducted to the atmosphere through achannel defined by the conduit 44, the two halves of the conduit 43, andthe secondary or auxiliary channels, 56. Upon leaving these secondarygases; on the contrary, with a flighthood properly designed it may. aidthe discharge of gases into the atmosphere. constitutes a welded sheetmetal construction having an outerwall fl and an inner wall 33 ing 34 inthe direction of the slipstream. The inner wall 33 has a cylindricalprojection surrounding the wheel l0 and with an edge portion biasedtowards'a grooved portion "of the nozzle box IQ. A central lower portionlot. -the inner wall 33 has an opening 31 through which the lbrackets 26project. An upper or forward curved portion 38 welded between th'e outerand inner walls has an opening 38 through which the inlet portion oi.the cooling conduit'lz projects. After assembly the opening 38 betweenthe cooling conduit 22 and the grooved nozzle bQX portion 36 is closedby a strip of metal or F closure member 48.

Upper or forward portions on of the flight hood form openings. 4| and 42which according to my invention are connected toreceive waste gas fromthe conduit 28 by-means including a curved conduit 43 with end portionssecured in the openings 4i and 42 and an upper central portion connectedto anfinlet conduit The flight hood proper means including a connectingsleeve Opposite sides 4 4, the latter being secured to the conduit 28 by49 means of a connecting or coupling device 45., More specifically theconduits 28 and 44 have adjacent end portions 46 conically' shaped orflared outward. These adjacent flared conduit end portions are engagedby a connecting ring 41 comprising two halves 48 and 49 with acontinuous inner groove, V-shaped in cross section 'and in engagementwith the flared end portions (Fig. 4). .In order to secure the two ringhalves 48, 49 together and thereby securely to connect the conduits28,'44,.each end portion of each ring half is provided with an eye tointegralhrunited with such end portions by a weld 5|. Theeyes 50 of theadjacent end portions of the ring halves 48 and '48 are detachably-tas-I ten'ed together by a bolt 52. With this connecting device 45 theconduits 28, 44 .may'be readily assembled and dismantled.

t is"des irable*to prevent mixing' of the waste gases with the .turbineexhaust gas in proximity 45 mg a channels the waste gases may mixwiththe tur-; bine exhaust gases. Such mixing, however, takes placeonlybeyond the trailing portion of the turbine wheel. The vvariouschannels are symmetrically arranged with regard to a diameter of the.bucket wheel.

Thegases discharged from the opening the flight hood may be confinedwithin a channel .51 indicated in dash-dotted lines andvcon- 5 nected tothe discharge end of the flighthood by Q8 to a point in the rear of theaircraft.

' cha flanged compressor casing 13 by means 0! brackets 59 and 60 fusedto the flighthood structure and bolted tothe flanged casing l3 by bolts8|.

With this arrangement the weight of the flighthoodis entirely carried bythe casing i3 and the load on the nozzle box [6 is reduced toa'minlmum.The box carries only th coo ling device 20. The separate supports forthe cooling device and the flighthood permit adjustment of the runningclearance between the coolingvcap 2i and the bucket wheel withoutafiecting the flighthood. likewise, the fiighthood may be adjustedwithout ailecting the adjustment of the cooling device 20.

Having described the method of operation of. my invention, together,with the apparatus which I now consider to represent the best embodimentthereon-I desire to have it understood that the apparatus shown is onlyillustrative andfthat the invention may becarried out by other means.

What I claim as new and desire to secure by ,Letters' Patentof theUnited States is: 1. Aircraft gas turbin arrangement comprisgas turbinehaving a bucket wheel mounted with its/axis substantially perpendicularto the direction of the slipstream and a nozzle box for conducting gasesto the wheel, a conduit for conducting gases to the nozzle box having avalved so wast gas conduit for bypassing gases with reto the"tuibinewheel in order to prevent or reduce after-burning and consequentexcessive tempe tures near the turbine. To this end partitions orbaiiles i3 and 54 are provided on-opnels 55 ,and.'56 respectively which,constitute extensions of the channels defined by the end portionsot thecurved conduit 431 The upper edges,

' posite sides of the wheel to define waste gas changard to thenozzlebox, and a combined flighthood and waste gas discharge deviceenclosing the discharge side of the wheel for discharging gases from thewaste gas conduit and the bucket wheel to the atmosphere, saidflighthoodhaving a discharge opening' located beyond the trailing portion of thewheel and an inlet opening radially outward-from the leading portion ofthe wheel I and connected tosaid conduit and a partition to formseparate channels forreceiving gases issuing from the wheel and wastegases from said conduit to preclude mixing of these gases in proximityto the wheel. I

2. Aircraft gas turbine arirangem'entcomprlsing a gas turbine having abucket wheel mounted with its axis substantially perpendicular to thedirection of the slipstream 'and a nozzle box, means including a wastegas conduit iorrconducting gases to the nozzle box andb'ypassing 7 gaswith regard to the nozzle box, and a comportionof the bucket wheel, thatis, near the discharge opening 34 of the flighthood.'

operation the gases exhausted irom the bucket wheelare conducted to theatmosphere bined flighthoo'd and waste gas discharge device fordischarging gases from the bucket wheel and thewaste gate conduit to theatmosphere, said device including a flighthood proper having in- 7 norandouter walls with a partition to form a The combined flighthood andwaste gas disrgedevice is detachably supported on the g mixing of thegases in proximity to the wheel.-

3. Aircraft gas turbine arrangement comprising a gas turbine having abucket wheel and a nozzle box for conducting gases to the wheel, conduitmeans having a valved waste gas conduit for conducting gases to thenozzle box, and a combined fiighthood and waste gas discharge device fordischarging the gases from the waste gate and the bucket wheel to theatmosphere, said device comprising a flighthood proper having inner andouter walls and partitions on opel, said channel 7 aaaaeoa posite sidesto define a main channel for receiv- 4 ing gases exhausted from theturbine and auxiliary channels, and conduitmeans connecting the wastegas conduit to the auxiliary channels.

4. Aircraft gas turbine arrangement comprising a gas turbine having abucket wheel and a nozzle box for conducting gases to the wheel, conduitmeans having a valved waste gas conduit for conducting gases to thenozzle box, a

combined flighthood and waste gas discharge device with a partition toform separate channels, on channel for receiving gases from the wastegate arid the other for receiving gases from the bucket wheel andconduct them to the atmosphere, the device having anoutletradiallyoutward of the wheel and facing rearward when viewed inthe direction of the slipstream, a coupling means detachably connectingthe device to the waste gas conduit, and adjustable means for supportingthe device so that a minimum load is carried by the nozzle box.

EUGENE s. cnami.

